Mining machine cutter bit



Nov. 6, 1956 J. F. JOY

MINING MACHINE CUTTER BIT Filed Oct. 28, 1948 [22?1622202 fish/7922 Jaiy.

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MINING MACHINE CUTTER BIT Application October 28,1948, Serial No. 57,046

4 Claims. (Cl. 262-33) This invention relates to cutter bits and more particularly to a cutter bit especially designed for use with mining machines.

In cutter bits, and especially those used with the cutter chains of coal cutting machines, it has become common practice to place hard metal inserts in the cutting points to increase the resistance to wear. Such hard metal inserts, which are usually composed of tungsten carbide, are usually secured, as by silver soldering or brazing, in recesses in the bit points, and considerable difficulty has been encountered in the proper securing of the inserts in place. Even with such hard metal inserts, it has been found necessary to resharpen the cutting points by grinding at intervals and difiiculty has also been encountered in the provision of adequate support for the inserts while attaining the desired cutting clearances. The present invention contemplates improvements over known types of cutter bits in that the hard metal inserts are secured in place in the bit points and adequately supported in an improved manner, thereby providing a cutter bit having a self-sharpening characteristic and improved wearing qualities, resulting in longer bit life. The hard metal inserts in the cutting point of the cutter bit of the present invention are secured in place and the cutting point is formed by a novel method. In certain embodiments the cutter bit has two cutting points and is reversible.

An object of the present invention is to provide an improved cutter bit. Another object is to provide an improved cutter bit especially designed for use with the cutter chain of a coal cutting machine. A further object is to provide an improved cutter bit having a hard metal insert set in a novel manner in the cutting point for improving the wearing qualities of the bit. A still further object is to provide an improved cutter bit having a selfsharpening cutting point. Yet another object is to provide an improved cutter bit having a cutting point of wear resisting material and formed in a novel manner. Other objects and advantages of the invention will, however, hereinafter more fully appear.

In the accompanying drawing there are shown for purposes of illustration one form and two modifications thereof which the invention may assume in practice.

In this drawing:

Fig. l is a side elevational view, partially in central longitudinal section, of a cutter bit constructed in accordance with an illustrative embodiment of the invention.

Fig. 2 is a front elevational view of the cutter bit shown in Fig. 1.

Fig. 3 is a detail sectional view taken on the plane of line 33 of Fig. 1.

Fig. 4 is an enlarged fragmentary sectional view taken on the plane of Fig. 3 showing the hard metal insert and the manner of holding the same in position on the cutting point of the bit.

Fig. 5 is a fragmentary view, partially in side eleva tion in section, showing the cutter bit in a step of partial completion.

Fig. 6 is a side elevational view, with a portion in section, illustrating a modified form of cutter bit.

Fig. 7 is a side elevational view illustrating another modified form of cutter bit with the bit shown in operative relation with respect to a conventional chain block.

First referring to the form of the invention shown in nited States Patent Figs. 1 to 5, inclusive, it will be noted that the cutter bit has a conventional rectangular shank 1 adapted for reception in a socket of a chain block of a conventional cutter chain, and formed integral with the shank at the outer end of the bit is an outwardly and forwardly tapered cutting portion 2 providing a cutting point or tip 3. The cutting portion 2 has a plane front face 4 extending forwardly and outwardly obliquely with respect to the bit shank, and an outer end surface 5 recedes from the cutting point. The cutting bit may be formed from a blank which may be forged or otherwise formed, and in Fig. 5 the partially formed cutting portion of the bit is shown at a step subsequent to the blank forging operation and prior to completion of the cutting point. After the blank forming operation, a recess herein a hole or bore 6 is suitably formed as by drilling in the cutting portion 2 with the hole axis in parallelism with the oblique front face 4 of the cutting portion with its front wall in adjacency to the front face. A hard metal insert 7 of cylindrical form and desirably composed of tungsten carbide is inserted in the hole 6 with its inner end resting firmly on the hole bottom, and is secured in the hole as by silver soldering, brazing or otherwise in a well known manner. The front face 4 of the cutting portion is then suitably cut away at 8, as by grinding, throughout a substantial portion of the length of the face, and by this cutting away operation the front wall of the bore is removed a substantial portion of its length and circumferentially through an arc of substantially 60 so that the front side of the insert throughout a substantial portion of its length is exposed. Thus a longitudinal slotlike opening is provided lengthwise of the bore-walls, while retaining a sufficient wall-area firmly to hold the insert against forward lateral release from the bore. Preferably, during this cutting away or grinding operation, the front face of the insert is flattened at 9 and the plane face thus provided extends to the cutting tip. The outer end surface 5 of the bit portion 2 may then be finished, as by grinding or otherwise, to provide a slightly rounded outer edge which may taper slightly rearwardly from the front cutting face of the bit point. The cutting portion 2 also has relatively inclined plane side surfaces 10 (Figs. 2 and 3) which slightly taper rearwardly and inwardly with respect to the front cutting face 11 of the bit point to provide the desired cutting clearance. By cutting away the front wall of the bore 6 in which the insert is secured, a narrow forward portion of the front face of the insert is exposed while the insert is firmly held against forward lateral release from the bore, and by the novel arrangement disclosed a self-sharpening characteristic is provided so that as the outer edge and side walls of the cutting point wear away a new portion of the hard metal insert is exposed to the work.

In the modification shown in Fig. 6, the novel cutting point construction of the form above described is embodied in a double ended reversible cutter bit 12 having a body 13 formed with relatively inclined arm portions 14 and 15 arranged at an obtuse angle. These arm portions have plane parallel front and rear surfaces 16 and 17 which intersect along parallel lines lying in a plane bisecting the bit body at the apex of the angle. These parallel surfaces terminate in the cutting portions 18 which provide cutting points or tips 19 at the opposite extremities of the bit. The cutting portions are formed in the same manner as the cutting portion of the first embodiment and have the same self-sharpening characteristic and improved wear resisting qualities. By setting the cutting points inwardly of the plane faces 16 of the bit body in the manner shown, the inactive cutting point is protected from engagernent with the bit support or block socket walls when the bit is secured in cutting position on its support or block.

In the modified embodiment shown in Fig. 7, the improved cutting portions of the embodiments above do adapted to meet the demands of service.

scribed are shown embodied in a double ended reversible cutter bit 21 which is designed for use with a conventional chain block shown in broken lines at 22 of a cutting machine cutter chain. The cutter bit has a body formed with relatively inclined portlons 23 and 24 which at their outer portions support the improved cutting points or tips 25. These cutting portions have parallel front and rear plane surfaces 26 and 27, and projecting rearwardly from the rear surfaces at the apex of the angle is an abutment 28 provided with opposed abutment surfaces 29, 29. The

' cutting points of the bit of this embodiment are formed in the same manner as in the embodiments above described, and the hard metal cutting points are set inwardly with respect to the front faces 26 in the manner similar to the embodiment shown in Fig. 6. The chain block 22 has a right angle socket 30 for receiving the inactive cut- 7 ting portion of the bit, and a usual set screw 31 engages the front surface 26 of the inactive portion to hold the a .rear surface 27 thereof against the rear socket wall. The

bit and are so shaped that as the cutting point or tip wears away, self-sharpening of the cutting point occurs due to wearing away of themetal at the outer ends cutting point or tip. By grinding the point surfaces at intervals the cutting point may be readily reshaped to keep it in its mosteifective cutting condition. method of manufacture, the hard metal insert is firmly held in position in the cutting portion of the bit. In the two modified embodiments, when one cutting point becomes dull'or unduly worn, the bit may be reversed end for end with respect to its support or block, therebyto present a sharp cutting point to the work. The grinding away of the front face of the cutting portion results in a setting back of the hard metal cutting point with respect to the front face of the bit,.thereby serving to protect the insert. from. injury when the bit is secured in position on 7 its support or block. In the embodiment last described,

not only may the bit be readily reversed when one point becomes dull, but also a predetermined bit gauge is provided. Thecutter bit of the several embodiments 'is not flush with said front face and extending to the'bit point p to provide a wear-resisting cutting tip.

2. A cutter bit comprising a bit body having a shank and an integral outer end portion provided with a plane front face obliquely disposed with respect to the longitudinal axis .of said shank and a receding outer surface, I

said front face and said receding outer. surface converging forwardly at the bitpoint, a recess of uniform cross section formed in said end portion in parallelism with said front face with said recess opening forwardly through said front face alonga substantial portion of the length 7 of said recess to provide .a narrowslot of'less width than the width of said recess, said recess opening outwardly. through said receding outer surface, and a hard metal. insert of pluglike form received and secured bybonding in said recess and having a plane narrow front 5 surface lying between the sides of said. narrow slotrandj said front flattened surface extending outwardly to said bit point to provide a wear-resisting cutting tip.

end cutting portion provided with an oblique front plane face and a receding outersurface, a hole of uniform. 1

and sides of the cutting portion of the bit to expose a new portion of the hard metal insert which provides the By this only simple in design, but is also extremely rugged; well Other advantages of the invention will'be clearly apparent to those skilled in the art. a

While there'are in this application specifically described one form and two modifications which the invention may assume in practice, it will be understood that theseforms and mode of practice are shown for purposes of-il'lustration and that the invention may be further modified and embodied in various other forms withoutideparting from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by .Letters Patent is: V

1. A cutter bit comprising a bit body having a shank and an integral outer end portion providing a plane front face disposed at asubstantial angle with respect to the longitudinal axis of the shank and a receding outer surface, said front face and said receding outer surface condrical pluglike form 'recelved and secured by bonding in said hole,.said slot being of less width than the diameter 7 "of said insert and said insert'having a flattened front surface coextensive with said slot, said flattened surface lying.

3. A cutter bit comprising a bit body having an outer circular cross section formed in said outer portion in parallelism with and in adjacency to said front face with the front wall of said hole' opening forwardly through said front face along a substantial portion of its length to provide a narrow slot of less width than thediameter of said hole, said hole opening outwardly. through said receding outer surface, and a hard metal insert of generally cylindrical pluglike form received and secured by bonding in said hole, said insert having a plane front face extending between the sides of saidslot substantially coextensive with .said slot, said plane frontface of said insert lying flush with said plane front face 'of said outer portion and extending to the cutting point to provide a wear-resisting cutting tip.--

4. A cutter bit comprising a b dy having a forwardly and outwardly projecting .outer end cutting portion providing a cutting point, a bore of uniform circular cross section formed in said cutting portion from its outer end surface withsaid bore opening through the-front side of said cutting portion to provide a narrow slot extending outwardly to the cutting point and of less width than the diameter of said bore, said slot extending into the front wall of said bore circumferentially through an arc cal pluglike form received and secured by. bondingin said bore and having a'narrow front portion exposed by said slot, said bore retaining sufficient Wall area for. firmly holding said insert against displacement from said bore and said'insert extending outwardly to the cutting point of the bit to provide a wear-resisting cutting tip;

References Cited in thefile of this patent 1 UNITED STATES PATENTS 1,415,021 De Bats May 9, 1922 1,902,513 Meutsch Mar. 21,1933

1,908,161 Meutsch May 9, 1933 1,908,208 Yass enotf May 9, 1933 1,951,174 Simons Mar. 13,1934 2,036,327 Fulke' Apr. 7, 1936 2,130,684 Hintermeyer Sept 20; 1938 2,183,581 Osgood Dec. 19,1939 2,289,464 Simmons July 14,; 1942 2,330,081 Phipps V Sept. 21,1943 2,418,320 Simmons Apr. 1, 1947 2,483,220 Morrow Sept. 27, 1949 2,521,089 Phipps Sept. 5, 1950 2,579,268 Malherbe Dec. 18, 1951 FOREIGN PATENTS 705,133 France Mar. 3, 1931 626,057 Germany Feb. 20, 1936' 670,880 Germany Jan. 26, 1939 655,633 Great Britain July 25, 1951 

